Post on 26-Jan-2020
© WJEC CBAC Ltd.
INTRODUCTION The marking schemes which follow were those used by WJEC for the January 2013 examination in GCSE SCIENCE - PHYSICS (LEGACY). They were finalised after detailed discussion at examiners' conferences by all the examiners involved in the assessment. The conferences were held shortly after the papers were taken so that reference could be made to the full range of candidates' responses, with photocopied scripts forming the basis of discussion. The aim of the conferences was to ensure that the marking schemes were interpreted and applied in the same way by all examiners. It is hoped that this information will be of assistance to centres but it is recognised at the same time that, without the benefit of participation in the examiners' conferences, teachers may have different views on certain matters of detail or interpretation. WJEC regrets that it cannot enter into any discussion or correspondence about these marking schemes. Unit Page P1 - FOUNDATION TIER 1 P1 - HIGHER TIER 4 P2 - FOUNDATION TIER 7 P2 - HIGHER TIER 10 P3 - FOUNDATION TIER 13 P3 - HIGHER TIER 16
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1
GCSE Science - Physics (Legacy) - P1
Mark Scheme
FOUNDATION TIER
Question Marking details Marks
Available
1. 230[V 50 Hz], 2450[MHz], 0.8 kW/800 W, 800 4
Question total [4]
2.
(a)
(b)
250 (1) 100 (1)
2400/150 = 16 years substitution (1), answer (1)
Question total
2
2
[4]
3. D A B E
3 or 4 correct = 3 marks
2 correct = 2 marks
1 correct = 1 mark
3
Question total [3]
4. (i)
(ii)
100/4 = 25 [p]
4/1.6 = 2.5 [h] substitution (1) answer (1)
Question total
1
2
[3]
5. (a)
(b)
(i)
(ii)
X rays / microwaves
UV / X rays / gamma
smaller / lower change in energy [of the charged particle]
Question total
1
1
1
[3]
© WJEC CBAC Ltd.
2
Question Marking details Marks
Available
6. (a)
(b)
(i)
(ii)
radiation
convection
2.5
5 = 50 [%] substitution (1) answer (1)
1
1
2
Question total
[4]
7.
(a)
(b)
(i)
(ii)
No fuel costs / limited pollution / generated immediately
Don’t accept renewable
An environmental decision
Step-up / change voltage (1) so that energy loss in the cables is
minimised. (1)
1
1
2
Question total [4]
8.
(a)
(b)
(i)
(ii)
(iii)
Box 2
Box 3
Box 1
Any 2 x (1):
More signals per cable / less interference / faster /more secure
Question total
1
1
1
2
[5]
9. (a)
(b)
(i)
(ii)
Any 2 x (1):
Lagging roof space / double glazing / draught excluding on doors etc
Bad conductor / traps heat (1) because of air gaps (1)
Prevents movement of air pockets in the cavity
Question total
2
2
1
[5]
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3
Question Marking details Marks
Available
10. (a)
(b)
(c)
(i)
(ii)
6325-5100 = 1225 (1)
7335-6325 = 1010 (1)
Units saved = 1225-1010 = 215 units (1) ecf
Money saved = 215 ecf x 43 = 9245 [p] / [£]92.45 (1)
Both answers to (a) x 43 award 1 mark only
No account taken of different conditions re: weather and gas charges
Question total
2
2
1
[5]
11. (a) (i)
(ii)
(iii)
(1.7 1.3)(1) 0.4
2 2
= 0.2[m] (1)
4
10/4 = 2.5 [m]
2
1
1
(b) Reduced [when speed is constant] 1
Question total
[5]
12. (a)
(b)
(c)
(i)
(ii)
(i)
(ii)
A group of rocks of various sizes orbiting the Sun / between Mars
and Jupiter
Between 350-650 [million km]
-50 and -100 [oC]
Inner rocky / outer gaseous
Sun’s radiant energy easily pushed the gases to the outer reaches
Question total
1
2
1
1
[6]
Total Foundation paper 50
© WJEC CBAC Ltd.
4
HIGHER TIER
Question Marking details Marks
Available
1. (a)
(b)
(c)
(i)
(ii)
6325-5100 = 1225 (1)
7335-6325 = 1010 (1)
Units saved = 1225-1010 = 215 units (1) ecf
Money saved = 215 ecf x 43 = 9245 [p] / [£]92.45 (1)
Both answers to (a) x 43 award 1 mark only
No account taken of different conditions re: weather and gas charges
Question total
2
2
1
[5]
2. (a) (i)
(ii)
(iii)
(1.7 1.3)(1) 0.4
2 2
= 0.2[m] (1)
4
10/4 = 2.5 [m]
2
1
1
(b) Reduced [when speed is constant]
Question total
1
[5]
3. (a)
(b)
(c)
(i)
(ii)
(i)
(ii)
A group of rocks of various sizes orbiting the Sun / between Mars
and Jupiter
Between 350-650 [million km]
-50 and -100 [oC]
Inner rocky / outer gaseous
Sun’s radiant energy easily pushed the gases to the outer reaches
Question total
1
2
1
1
[5]
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5
Question Marking details Marks
Available
4. Kettle:
2000 (1) 2(1) ecf on power (W) conversion
Food mixer:
5
60x 0.72 = 0.06 (1) correct power (1), conversion (1)
Answer of 3.6 with no working shown award 1 mark
Answer of 3.6 with working shown award 2 marks
5
Question total
[5]
5.
(a)
(b)
(i)
(ii)
(i)
(ii)
Award (1) x 3:
By conduction through the metal (1), radiates heat to people directly
in front of the radiation (1), air in contact becomes heated and rises –
circulating the room / forming convection currents to heat the room
(1) mechanism of convection (1).
Dark colours are best radiators / emitters of heat
Conduction [through ceiling] (1) and mainly convection [through the
roof space] (1)
Air gaps in fibre glass reduces conduction through the ceiling (1) and
[as a consequence] reduces convection since little heat conducted (1)
Question total
3
1
2
2
[8]
© WJEC CBAC Ltd.
6
Question Marking details Marks
Available
6. (a)
(b)
(i)
(ii)
(iii)
Any 3 x (1):
Localised heating effects e.g. rivers
Inefficient (can be implied)
Carbon dioxide / CO2 leads to global warming
Sulphur dioxide / SO2 leads to acid rain
% efficiency = useful power transfer x 100
total power input
82 400328
100
x [MW] substitution (1) answer (1)
328-118=210 [MW]
To minimise heat losses / ease of access to the energy / benefit to more
people
Question total
3
1
2
1
1
[8]
7.
(a)
(b)
(i)
(ii)
(i)
(ii)
Forces unbalanced, radiation pressure greater than gravity
Correct sequence red giant to white dwarf (1)
Any 2 points from the graph relevant to the red giant or white dwarf (1)
(don’t accept reference to colour)
More energy produced by fusion / more hydrogen to fuse
Any 3 x (1):
Expand to a red supergiant (1) and cools (1) and eventually becomes a
supernova (1) leaving behind a black hole / neutron star (1)
Question total
1
2
1
3
[7]
8. (a)
(b)
(i)
(ii)
Satellite takes the same time to orbit / 24 hours (1) as it takes for the
Earth to spin once on its axis (1)
8
9
3 100.06
5 10
x
x [m] substitution (1) answer (1)
7
8
2(1) 3.6 100.24
3 10
x x
x [s] substitution (1) answer (1)
Question total
2
5
[7]
Total Higher Tier 50
© WJEC CBAC Ltd.
7
GCSE Science - Physics (Legacy) - P2
Mark Scheme
FOUNDATION TIER
Question Marking details Marks
Available
1. (a) (i) H and A 1
(ii) G and B 1
(b) Good insulator / poor conductor or implied 2
Question total [4]
2.
(a)
(b)
150 x 2 = 300 [J] substitution (1) answer (1)
Energy required to operate lifting gear
Question total
2
1
[3]
3. (a) Statement (ii) (1)
Low level radiation from surroundings (1)
2
(b) (i) 108
5(1) = 21 / 22 [cpm] (1)
2
(ii) Statement 2 1
Question total [5]
4. (a)
(b)
(c)
6 400 [W]
6400
230= 27.8 [A] Substitution (1) answer (1)
m.c.b. needs a value above 28 A / too much current for the m.c.b.
Question total
1
2
1
[4]
5. Any 2 x (1) from:
Containment / safe transport / long activity / highly radioactive
Question total
2
[2]
© WJEC CBAC Ltd.
8
Question Marking details Marks
Available
6. (a)
(b)
(i)
(ii)
8 [m]
2 [s]
8
2(1) ecf = 4 [m/s] (1)
1
1
2
Question total
[4]
7.
(a)
(b)
(i)
(ii)
(iii)
Measure voltage (1)
Measure current (1)
Change resistance / change meter readings / change current / change
voltage across the coil (1)
6
1.5= 4 [] Substitution (1) answer (1)
3
2
Question total [5]
8.
(a)
(b)
(c)
(i)
(ii)
Computer generated from readings picked up by gamma camera
Low energy gamma [emitter] / easily escapes the body
640
24 [hours]
Question total
1
1
1
1
[4]
9. (a)
(b)
(c)
Straight line to (50,25) (1)
Straight line from (50,25) to (60,0) (1) ecf
Accelerates / uniform increase in speed / increase speed to 25 m/s
25 0
10
ecf from graph = 2.5 [m/s
2] Substitution (1) answer (1)
Question total
2
1
2
[5]
© WJEC CBAC Ltd.
9
Question Marking details Marks
Available
10. (a)
(b)
(i)
(ii)
120 [cpm] (1)
300-250 = 50 [cpm] (1)
This was amount absorbed by the aluminium plate (1) and beta are
absorbed by aluminium (1)
Question total
2
2
[4]
11. (a) 2 000 [N] 1
(b) (i)
(ii)
3 200 – 2 000 = 1 200 [N]
Acceleration = Resultant force
Mass
1200
800ecf = 1.5 [m/s
2]
1
1
2
Question total
[5]
12. (a)
(b)
(c)
(i)
(ii)
B is connected to the fuse (not goes through the fuse box)
S1 and S2 in position to control lamp X and lamps Y and Z (2 x (1))
Both S1 and S2 on live side (B) (1)
Currents in excess of 5 A (1) melts / breaks the fuse (1)
Question total
1
3
2
[6]
Total Foundation paper 50
© WJEC CBAC Ltd.
10
HIGHER TIER
Question Marking details Marks
Available
1. (a)
(b)
(i)
(ii)
120 [cpm] (1)
300-250 = 50 [cpm] (1)
This was amount absorbed by the aluminium plate (1) and beta are
absorbed by aluminium (1)
2
2
Question total
[4]
2. (a) 2 000 [N] 1
(b) (i)
(ii)
3 200 – 2 000 = 1 200 [N]
acceleration = resultant force
mass
1200
800ecf = 1.5 [m/s
2]
1
1
2
(c) Drag increases as speed increases (1) until it equals the new driving
force (1)
Or drag becomes equal to the new driving force (2)
Question total
2
[7]
3. (a)
(b)
(c)
(i)
(ii)
B is connected to the fuse
S1 and S2 in position to control lamp X and lamps Y and Z (2 x (1))
Both S1 and S2 on live side (B) (1)
Currents in excess of 5 A (1) melts / breaks the fuse (1)
1
3
2
Question total [6]
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11
Question Marking details Marks
Available
4. (a) (i) C-14 atoms / their nuclei (1) decay emitting an electron (1) 2
(ii) In 5 700 years (1) the activity / number of C-14 atoms halves (1) 2
(b) (i) Dead wood decays, therefore decreasing the activity (1) not taking in
C-14 (1) or living wood maintains its activity level (2)
2
(ii) 7 000 [years] Accept: 6 800 – 7 200 1
c)
(d)
Any 3 x (1) from:
Dangerous to humans
Costly because of containment
Site / transport
Length of time it is active
X activity = 80 (1) and Y activity = 40 (1)
[120 cps]
3
2
Question total
[12]
5.
(a)
(b)
(i)
(ii)
Doubles
Quadruples
[increase / increase earns 1 mark only]
24(1) + 160(1) = [184 m]
Question total
1
1
2
[4]
© WJEC CBAC Ltd.
12
Question Marking details Marks
Available
6.
(a)
(i)
(ii)
Z (1)
Y (1)
2
(b) (i)
(ii)
2.3 x 1000 = I x 230 Substitution (1) manipulation (1)
I = 10 [A] (1)
R = 230
10(1) ecf = 23 [](1)
3
2
(c)
Faster acting (1)
More sensitive / detects small changes in current (1)
Question total
2
[9]
7.
(i)
(ii)
(iii)
Work done by engines:
2 x 105 x 60 = 1.2 x 10
7 [J](1)
Work done by catapult:
10.8 x 105 x 60 = 6.48 x 10
7 [J](1)
Total work done = 7.68 x 107 [J](1) ecf
½ x 24 000 x v2 = 7.68 x 10
7 (1) ecf
v2 =
72 7.68 10
24000
x x(1)
v2 = 6 400
v = 80 [m/s] (1)
60
80(1) ecf = 0.75 [s](1)
Question total
3
3
2
[8]
Total Higher Tier 50
© WJEC CBAC Ltd.
13
GCSE Science - Physics (Legacy) - P3
Mark Scheme
FOUNDATION TIER
Question Marking details Marks
Available
1. A transverse wave (1)
Can travel through solids (1)
Travel slower than P waves (1)
3
Question total [3]
2. Diagram with defined nucleus (1) containing 3 protons and 4
neutrons (1) 2 orbits (1) with 2, 1 electrons (1)
4
Question total [4]
3.
(i)
(ii)
1 200 x 20 = 24 000 [kg m/s]
Greater mass / more momentum
Question total
1
1
[2]
4. (i)
(ii)
B (1) empty space (1)
A / C (1) nucleus (1)
4
Question total [4]
5. (a)
(b)
(i)
(ii)
(iii)
BC
Largest gradient / steepest line
Speed changes (1) from low to high value (1)
50
3.5 (1) = 14.28 [km/h] (1)
Question total
1
1
2
2
[6]
© WJEC CBAC Ltd.
14
Question Marking details Marks
Available
6. (a)
(b)
Any (1) x 2:
Fusion is joining together of two atoms
Releases more energy
Produces no radioactive waste
Readily available source of atoms
Fission statements acceptable alternatives
Any (1) x 2:
The extremely high temperatures required.
Safe containment for the reaction.
2
1
Question total
[3]
7. (a)
(b)
(c)
(i)
(ii)
3 waves drawn (1) perpendicular to wave direction (1)
Refraction
Decreases (1)
Decreases (1)
Question total
2
1
2
[5]
8.
(a)
(b)
(i)
(ii)
(iii)
1, 2 and 5 (1)
Faster than S waves (1)
Nearest to the earthquake (1)
Change of medium / solid liquid
3
1
Question total [4]
9.
(a)
(b)
E A D C
3 or 4 correct = 3 marks
2 correct = 2 marks
1 correct = 1 mark
Less turns on secondary / more turns on primary
Question total
3
1
[4]
© WJEC CBAC Ltd.
15
Question Marking details Marks
Available
10. (a)
(b)
(c)
25
10 (1) = 2.5 [m/s
2] (1)
½ x 20 x 25 = 250 [m] (1) (substitution (1))
Larger area for the last 30 s
Question total
2
2
1
[5]
11. (a) (i)
(ii)
Capture (1) of slow neutrons (1)
Graphite slows (1) up neutrons to enable fission (1)
Award a maximum of 3 marks in total for (a).
3
(b) Reduces output (1) since more neutrons are absorbed / so less fission
(1)
2
Question total
[5]
12. (a)
(b)
(c)
0.4 [s]
BA
Decreased (1)
Increased (1) Decreased (1)
Question total
1
1
3
[5]
Total Foundation paper 50
© WJEC CBAC Ltd.
16
HIGHER TIER
Question Marking details Marks
Available
1. (a)
(b)
(c)
25
10 (1) = 2.5 [m/s
2] (1)
½ x 20 x 25 = 250 [m] (1) (substitution (1))
Larger area for the last 30 s
Question total
2
2
1
[5]
2. (a) (i)
(ii)
Capture (1) of slow neutrons (1)
Graphite slows (1) up neutrons to enable fission (1)
Award a maximum of 3 marks in total for (a).
3
(b)
(c)
(d)
Reduces output (1) since more neutrons are absorbed / so less fission
(1)
To prevent escape of radiation – stray neutrons (1)
Protection for workers / community / environment (1)
a = 92 – 36 = 56 (1)
b = 236 – 146 = 90 (1)
Question total
2
2
2
[9]
3. (a)
(b)
(c)
(d)
0.4 [s]
BA
Decreased (1)
Increased (1) Decreased (1)
Any 2 x (1):
Radial fields
Multi-coils
Electromagnets rotate
Rotor & stator
Question total
1
1
3
2
[7]
© WJEC CBAC Ltd.
17
Question Marking details Marks
Available
4. (a)
(b)
Transverse vibrations (1) at right angles to direction (1) / longitudinal
vibrations (1) along direction (1)
Any (1) x 5:
Speed increases with depth in the mantle (1)
Speed increases with depth in the core (1)
No S waves in the core (1)
Core must be a liquid (1)
Abrupt change of speed shows boundary (1)
Size of mantle (1)
Size of core (1)
P wave speed constant through solid inner core (1)
2
5
Question total [7]
5.
(a)
(b)
(c)
(i)
(ii)
Alpha (1)
Beta (1)
230 – 90 = 140
A
Question total
2
1
1
[4]
© WJEC CBAC Ltd.
18
Question Marking details Marks
Available
6.
(a)
(i)
(ii)
Core has a changing field (1) which links with secondary coil (1)
Fewer turns (1)
3
(b)
(c)
No changing field with d.c.
1 1
2 2
V N
V N
2
230 4600
40V (1 for substitution) (1 for manipulation)
2
230
115V 2 [V] (1)
1
1
3
Question total
[8]
7.
(a)
(b)
(c)
(i)
(ii)
(i)
(ii)
v2 = u
2 + 2ax
2402 = 2 x a x 0.6 (1)
a = 48 000 [m/s2] (1)
1( )
2x u v t
2400.6
2t (1)
t = 0.005 [s] (1)
Momentum before = Momentum after
0.02 240 2 (1)
0.02 240
2
x v
xv
v = 2.4 [m/s] (1)
2
2
mvKE (1)
20.02 240
2
x= 576 [J] (1)
Some lost as heat (1)
Some lost doing work against bullet’s penetration of target (1) Accept: change in shape of target
Question total
2
2
2
2
2
[10]
Total Higher Tier 50
GCSE SCIENCE - PHYSICS (LEGACY) MS - January 2013
© WJEC CBAC Ltd.
WJEC 245 Western Avenue Cardiff CF5 2YX Tel No 029 2026 5000 Fax 029 2057 5994 E-mail: exams@wjec.co.uk website: www.wjec.co.uk